refactor: Transport trait and worker transport, and streamable http client with those new features. (#167)

* refactor: a transport trait and streamable http client

* test: test with js streamable http server

* refactor: separate sse stream connection

* fix(test): streamable http client test with js

* fix(test): wait longer time for js server startup

crates/rmcp/tests/test_with_js/package.json

@@ -1,7 +1,8 @@
 {
   "dependencies": {
     "@modelcontextprotocol/sdk": "^1.10",
-    "eventsource-parser": "^3.0.1"
+    "eventsource-parser": "^3.0.1",
+    "express": "^5.1.0"
   },
   "type": "module",
   "name": "test_with_ts",